Californians who have health insurance aren’t immune from medical debt according to a new survey from UCLA.

Shana Alex Lavarreda is a co-author of the UCLA Center for Health Policy Research report about health insurance in California. She says in the 2007 survey the center asked about medical debt. And it found thirteen percent of people – or more than two million Californians – reported owing money for health care they’d received. She says surprisingly many of them had insurance.

“Two thirds of Californians who have medical debt were insured.”

Lavarreda says the survey found striking regional differences in medical debt as well.

“In the Northern and Sierra counties of California the percentage of people with medical debt was up to almost 25 percent. It was absolutely the highest in the state.”

According to the report, Humboldt County had the highest rate of medical debt, 39 percent. San Mateo County had the lowest at seven percent. Sacramento, Los Angeles and the Bay area had rates of about 10 percent of residents owing money. Some causes of the debt include high deductible insurance plans and co-pays as well prescription drug costs and limited access to care. Lavarreda predicts more Californians will have debt in the 2009 survey underway now because of the recession.